Answer:
y = -5.5x - 20
Explanation:
There are many functions that cross those points.
Assuming you're looking at a straight line.
y = mx + b
15/2 = -5m + b --> 7.5 = -5m + b
-73/2 = 3m + b --> -36.5 = 3m + b
Subtract the first from the second.
-44 = 8m
m = -5.5
Plugging back into the first equation, we get b = -20